1. Field of the Invention
The present invention relates generally to air filters and more particularly to a self-adhesive air filter for use in forced air climate control systems.
2. Background and Summary of the Invention
The use of air filters to remove particulate matter from an airflow is well known. Modern air filters are generally comprised of a filtering media and a support means to provide support to the filtering media. Typically, the filtering media is comprised of a substantially flexible fibrous material, either of natural and/or synthetic origin, that is capable of retaining particulate matter contained in an airflow passing through the filtering media. Typically, the support means is a frame or bracket that extends around the periphery of the filtering media.
With respect to modern climate control systems that employ the use of forced air, such as certain heating, ventilation, and air conditioning (HVAC) systems, there has been significant interest in the development of suitable air filters that can remove particulate matter from the airflow while simultaneously preventing damage to the climate control system. Conventional air filters are usually available only in pre-sized full frame styles which restrict their use to a relatively narrow range of possible register sizes. Recent air filtering techniques have included the direct mounting of the filtering media to the exterior surface of an air supply or air return register. However, this technique includes the inconvenience and cost of secondary attachment means.
U.S. Pat. No. 3,458,130 discloses that in lieu of a single removable large air filter disposed in the furnace adjacent the blower, a relatively small air filter fitting tightly on each of the individual cold air registers (i.e., air return registers) is employed. These small air filters are secured to the air return registers with a band of adhesive that extends along the entire periphery of the air filter, thus forming an air-tight seal about the air return register.
U.S. Pat. No. 4,340,402 discloses a dual air filter system comprising a releasably securable disposable secondary filter comprised of polypropylene secured to a disposable or permanent primary filter comprised of fiberglass. The dual air filter is intended for use with heaters and air conditioners.
U.S. Pat. No. 4,889,542 discloses a filter panel adhesively attached to the outside of a computer housing to cover the air intake grids used to draw air into the housing by a draft from a cooling fan in the housing. The filter is comprised of a porous permeable reticulated flexible polyester polymeric foam about 1/4 inch thick with a continuous adhesive strip on the back side to removably attach the foam over the air intake opening.
A vent filtration kit marketed by National Allergy Supply, Inc. comprises polyester filters to remove dust coming out of ductwork (i.e., air supply registers). The filters fit over or under the air supply registers. The filters are secured to the supply registers with Velcro.TM. strips that are mounted to the exterior surfaces of the supply registers.
Although these filtering devices may, to a certain extent, reduce the amount of particulate matter in an airflow, they are also capable of causing damage to the climate control system, especially a forced air climate control system. For example, when the above-described filters, especially those mounted over an air supply register, become substantially saturated with particulate matter, the airflow through the filters may become blocked to the point where airflow ceases to pass through the filters. At that point a potentially dangerous situation may arise where air pressure is rapidly built up about the air supply register. Because the airflow can not escape through the filter, due primarily to the airtight seal formed about the air supply register with conventional air filters, the airflow is forced backed toward the furnace. This can lead to substantial damage to the climate control system.
Therefore, there exists a need for a filtering device that can be used with a register of a forced air climate control system, especially an air supply register, wherein the filtering device allows the airflow to bypass the filtering device when it becomes substantially saturated with particulate matter.
In accordance with one embodiment of the present invention, a filtering device for use with a register in a forced air climate control system comprises a filter substrate having a first major face and a second major face for filtering particulate matter from air flowing through the filter substrate, wherein the air flows in a direction ranging from substantially perpendicular to substantially oblique to the major faces. An adhesive layer is disposed in a discontinuous pattern on the second major face and is arranged thereon to permit removable attachment of the filter substrate to the register while simultaneously providing passageways parallel to the second major face for allowing air to escape from the edges of the filter substrate when the filter substrate has become substantially saturated with particulate matter.